1. Field of the Invention
The present invention relates to the structure and method of concrete reclaiming. The instant invention allows the user to easily separate cement slurry, sand and gravel from mixed concrete for future use.
2. Description of Background Information
It is known to breakdown mixed concrete to its constituent parts of cement slurry, sand and gravel. It is also well known to employ rotating screens or trommels for filtering and separating different sized granules of sand and gravel in the reclaimer. There are reclaimers that employ screw type conveyors for advancing product through the reclaimer and there are reclaimers that use only the force of gravity to advance their product.
In screw type conveyor reclaimers, the screw conveyor is required to extend along the entire length of the reclaimer cylinder. In the screen chambers of such reclaimers there is a likelihood of clogging or jamming due to the screw conveyor forcing product past the screen element.
Additionally, such reclaimers are inefficient because they work against the force of gravity. Screw conveyors force the product through the reclaimer chambers instead of allowing the force of gravity to move the product.
In reclaimers employing only gravity for advancing product through the reclaimer chamber, several screen chambers or trommels are required for reducing the mixed concrete to its constituent parts. Such reclaimers may allow too much product into the reclaimer chamber. In this event, the forces of gravity may pull the concrete mixture past the screen chamber before the mixture is fully filtered or separated for the relevant granule size.
PREISSER, U.S. Pat. No. 5,312,051, discloses a declining reclaimer apparatus with a plurality of rotating screens of increasing mesh size. As shown in FIGS. 1 and 2, fresh concrete poured into the upper inclined end 22 of the reclaimer migrates to the lower declined end. As the concrete runs through the plurality of rotating screen chambers 14a, 14b, the concrete mixture is separated into cement slurry A, sand S and gravel G. This device requires separate screens for the cement slurry A and sand S. Gravel G is discharged through the end of the reclaimer. Because this particular apparatus provides no means for regulating the admission of mixed concrete into the opening 22, too much concrete may be in chambers 14a, 14b resulting in improper filtration or separation. This improper result is due to the pull of gravity on the concrete product through the particular screen chambers before the product is fully filtered.
TANII, U.S. Pat. No. 5,082,553, discloses a concrete reclaimer apparatus that moves the mixed concrete product through the device by a screw type conveyor means. FIG. 3 shows that the device requires a screw conveyor 16 to move the mixed concrete into the screen chamber 9. Another screw conveyor 24 is required to move the product through the screen chamber 9 and to discharge reclaimed gravel into chute 26a, 26b. A third screw conveyor 27 is required to discharge the sand 18 into chute 30a, 30b. This device suffers from the same drawbacks as other screw conveyor type reclaimers in that the device may become clogged or jammed. While this particular device provides a method and means for jam relief, this device is unable to avoid a jam. This device is also inefficient in that it works against the force of gravity by pushing the concrete mixture through the reclaimer by screw conveyor means 16, 24, 27.
MILLER, U.S. Pat. No. 4,127,478, discloses an inclined concrete reclaimer. FIG. 1 shows the mixed concrete product inserted into chute 18. The product is advanced upward and through the reclaimer by screw conveyor 22 past screens 26, 27. The screens 26, 27 filter fine and coarse sand granules. This device suffers from a propensity to clog or jam. Also, this device is wholly inefficient. Not only does this device push product through the reclaimer, but it pushes the product upward against the force of gravity. MILLER also provides a means for rotating the reclaimer in which drive wheels 20 are disposed on either side of the lower declined end of the reclaimer. On the upper inclined end are a pair of idler wheels 21. This arrangement is inefficient. The drive wheels 20 are required to not only rotate the reclaimer chamber 19, but also to advance the concrete product upward against the force of gravity.
HILKEMAIER, U.S. Pat. No. 2,983,378, discloses an inclined concrete reclaimer requiring only one screen to separate the mixed concrete into its constituent parts of cement slurry, sand and gravel. FIG. 2 shows the reclaimer apparatus in which a screw conveyor 15, 16 is employed to push the mixed concrete up and through the screen chamber 26 and discharge end 8. This device suffers from the same inefficiency and propensity to clog or jam as the other screw type inclined concrete reclaiming apparatuses.